Carbon-Based electronics manipulate electrons as waves

March 15, 2006 | Source: KurzweilAI

Using thin layers of graphite known as graphene, researchers have produced proof-of-principle transistors, loop devices and circuitry. The devices have the attractive properties of carbon nanotubes but could be produced using established microelectronics manufacturing techniques.

Ultimately, the researchers at the Georgia Institute of Technology in the United States, in collaboration with the Centre National de la Recherche Scientifique, hope to use graphene layers less than 10 atoms thick as the basis for revolutionary electronic systems that would manipulate electrons as waves rather than particles, much like photonic systems control light waves.

They start with a wafer of silicon carbide, a material made up of silicon and carbon atoms. By heating the wafer in a high vacuum, they drive silicon atoms from the surface, leaving a thin continuous layer of graphene.

Next, they spin-coat onto the surface a photo-resist material of the kind used in established microelectronics techniques. Using optical lithography or electron-beam lithography, they produce patterns on the surface, then use conventional etching processes to remove unwanted graphene.

They’ve created feature sizes as small as 80 nanometers — on the way toward a goal of 10 nanometers. The graphene circuitry demonstrates high electron mobility — up to 25,000 square centimeters per volt-second, showing that electrons move with little scattering. The researchers have also shown electronic coherence at near room temperature, and evidence of quantum interference effects.

So far, they have built an all- graphene planar field-effect transistor. The side-gated device produces a change in resistance through its channel when voltage is applied to the gate. The researchers have also built a working quantum interference device, a ring-shaped structure that would be useful in manipulating electronic waves.

Source: Georgia Institute of Technology news release